The file is not available

Sorry, English is from Google translate.

In “My library” the songs that I drag from the Finder, it tells me “The file is not available”. The other day it worked, but not today. The titles of the songs are gray.

If I look for the songs from Djay Pro’s “Finder”, it does find them and load them. But not from “My Library”.

Resolved: file deleted where it stores the playlists.

Unfortunately you lose the playlists …